Four NIH Institutes (NICHD, NIMH, NINDS, and NIDA) have jointly sponsored a multicenter study to advance our understanding about how the brain develops in typical, healthy children and adolescents. This study is enrolling approximately 500 children, ranging from infancy to young adulthood, who are being seen at different time points over a six year period (2001-2007) at several clinical centers around the U.S.. Magnetic Resonance Images (MRI) of the brain are being performed and the imaging findings are being related to the results of standardized neuropsycological tests. [unreadable] [unreadable] Our role is to serve as a Diffusion Tensor Data Processing Center (DPC). This entails processing and analyzing all diffusion tensor MRI (DTMRI or DTI) data that is being acquired by the various Centers during the course of the study. Previously, we have been developing and implementing the DTI data processing pipeline. Specifically we developed procedures for sorting, displaying, and co-registering diffusion weighted images from which the DTI data is computed. The image registration procedure accomplishes the tasks of removing the effects of subject motion and eddy current distortion as well as aligning the images to a given template with only one interpolation step, ensuring minimal data quality loss. We also proposed a new strategy for robust estimation of the diffusion tensor and quantities derived from it. We addressed the task of registering DTI data to other structural MRI data contained in the database using rigid body and linear (affine) transformations. More recently we addressed the task of correcting residual image distortion originating from the Echo-Planar Image (EPI) acquisition used for DTI.[unreadable] [unreadable] In 2005 the project was awarded Neuroscience Blueprint funds to expand the DTI portion of the study. The original DTI data collection was limited to only a 10 minute protocol performed on those subjects able to tolerate additional time in the scanner following the collection of the core structural MRI data. This expansion will increase the quality and quantity of data collected through longer or additional scanning sessions for older subjects, and through the recruitment of new subjects and scanning sessions for the younger cohort. Our group has designed the expanded DTI protocol and coordinated its implementation at each acquisition site. [unreadable] [unreadable] Data collection will be completed by the end of August, 2007 and soon after all raw diffusion data and structural MRI targets are expected to be made available to us for systematic processing. We plan to produce processed diffusion data that can be made available to the scientific community in about a year after receiving all raw data.